Ventilation help!

I have a small grow box the size of 1'x2'x3'. I am growing with 6 35 watt cfls. My last problem is the ventilation. I have no option to poke holes in the walls of the grow box or set up a "push and pull" ventillating system. Would i be fine if i just placed a small osculating fan inside the box and let the air move around in there, from time to time opening the door to the grow box to let fresh air in?
 
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